The present invention relates to a plasma processing system using a plasma of a process gas for processing a substrate such as a semiconductor wafer or the like by a plasma process, such as plasma etching process.
Minimum device dimensions specified by pattern rules have progressively been decreased with the ongoing miniaturization of semiconductor devices and the growth of the number of components per IC chip. Accordingly, fine etching techniques have become particularly indispensable to the fabrication of semiconductor devices. Integrated circuit fabrication processes that use plasma etching processes are most prevalent at present.
Generally, a RF capacitive coupled reactor is used to carry out a plasma etching process. A reactive ion etching system (RIE system), which applies a RF voltage to an electrode supporting a wafer and uses the physical actions of radicals and ions, is capable of highly anisotropic etching and is suitable for fine processing.
Incidentally, the reaction vessel of the RIE system needs to be maintained at a relatively high pressure of several hundreds mTorrs in view of achieving highly reactive etching. In such a reaction vessel, a relatively large amount of dust of reaction byproducts is produced, which tends to reduce the yield rate of semiconductor devices requiring fine processing.
High-energy ions impinge on a semiconductor wafer during the operation of a RIE process and thereby charge-up damage, i.e., the destruction of devices by charge-up, is liable to be caused.
Efforts have been made to determine appropriate process conditions through the simulation using various parameters to simulate the condition of a plasma. However, any plasma etching process using properly controlled plasma has not successfully been developed so far through the adjustment of the generally known parameters.